State forces discovered at least 79 million Philippine pesos (about $1.6 million) in cash and checks on June 5 in a house in Marawi City that had been occupied by Maute fighters.

The source of the money was being investigated.

On June 4, Philippine Defense Secretary Delfin Lorenzana said that it was clear the Marawi conflict was backed by Islamic State due to the amount of foreign fighters involved.